package com.haoxin.ai_course.common.utils;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import java.security.spec.InvalidParameterSpecException;
import java.util.Arrays;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.tomcat.util.codec.binary.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;


public class AesUtils {
	  /**
     * 解密工具直接放进去即可
     */
    public static String decryptS5(String encryptedData, String sessionKey, String iv) {
    	/**
         * 微信小程序解密
         * @param encryptedData
         * @param sessionKey
         * @param iv
         * @return
         */
    	try {
			encryptedData = URLEncoder.encode(encryptedData,"UTF-8").replace("%3D","=").replace("%2F","/");
			sessionKey = URLEncoder.encode(sessionKey,"UTF-8").replace("%3D","=").replace("%2F","/");
			iv = URLEncoder.encode(iv,"UTF-8").replace("%3D","=").replace("%2F","/");
		} catch (UnsupportedEncodingException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
            String result = "";
            // 被加密的数据
            byte[] dataByte = Base64.decodeBase64(encryptedData);
            // 加密秘钥
            byte[] keyByte = Base64.decodeBase64(sessionKey);
            // 偏移量
            byte[] ivByte = Base64.decodeBase64(iv);
            try {
                // 如果密钥不足16位，那么就补足. 这个if 中的内容很重要
                int base = 16;
                int keyLength = keyByte.length ;
                if (keyLength % base != 0) {
                    int groups = keyByte.length / base
                            + (keyByte.length % base != 0 ? 1 : 0);
                    byte[] temp = new byte[groups * base];
                    Arrays.fill(temp, (byte) 0);
                    System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
                    keyByte = temp;
                }
                // 初始化
                Security.addProvider(new BouncyCastleProvider());
                Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding", "BC");
                SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
                AlgorithmParameters parameters = AlgorithmParameters
                        .getInstance("AES");
                parameters.init(new IvParameterSpec(ivByte));
                cipher.init(Cipher.DECRYPT_MODE, spec, parameters);// 初始化
                byte[] resultByte = cipher.doFinal(dataByte);
                if (null != resultByte && resultByte.length > 0) {
                    result = new String(resultByte, "UTF-8");
                }
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            } catch (NoSuchPaddingException e) {
                e.printStackTrace();
            } catch (InvalidParameterSpecException e) {
                e.printStackTrace();
            } catch (IllegalBlockSizeException e) {
                e.printStackTrace();
            } catch (BadPaddingException e) {
                e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (InvalidKeyException e) {
                e.printStackTrace();
            } catch (InvalidAlgorithmParameterException e) {
                e.printStackTrace();
            } catch (NoSuchProviderException e) {
                e.printStackTrace();
            }
            return result;

    }
}
